Ring Expansion of Oximes via Photochemical Aza-di-π-methane Rearrangement

Area of Science:

• Organic Chemistry
• Photochemistry
• Radical Chemistry

Background:

• Skeletal editing enables manipulation of cyclic structures.
• Radical-based methods offer mild and versatile synthetic routes.
• Visible-light-driven diradical chemistry for molecular editing is underexplored.

Purpose of the Study:

• To develop a novel visible-light-driven ring expansion of cyclic oximes.
• To utilize diradical intermediates for photochemical skeletal editing.
• To establish an efficient and mild synthetic methodology.

Main Methods:

• Photochemical aza-di-π-methane rearrangement.
• Visible-light irradiation with energy transfer catalysis.
• Diradical intermediate generation and transformation.

Main Results:

• Achieved unprecedented visible-light-driven ring expansion of cyclic oximes.
• Demonstrated broad substrate scope and excellent functional group tolerance.
• Showcased versatile downstream reactivity of the rearranged scaffolds.
• Successfully adapted the transformation for photochemical continuous-flow conditions.

Conclusions:

• The diradical-mediated photochemical rearrangement provides a mild and efficient synthetic route.
• This method expands the available strategies for radical-based ring expansions.
• The developed transformation complements existing classical approaches like the Dowd-Beckwith reaction.